getting 500 error while installing on linux server

Hi All,
I am getting 500 error while installing silverstripe. And on apache log i am getting following error.
SoftException in Application.cpp:256: File "/home/examwind/public_html/silver/sapphire/main.php" is writeable by group

File "/home/examwind/public_html/silver/sapphire/main.php" is writeable by group

Thats an interesting error message, Is that the only one you get? seems like its more of a security warning than something that worth throwing a 500 error about. But if thats the thing its complaining about then remove the group write permissions. On UNIX then would be chmod g-w sapphire/main.php